emergency (n.)

"to rise from or out of anything that surrounds, covers, or conceals; come forth; appear, as from concealment," 1560s, from French émerger and directly from Latin emergere "bring forth, bring to light," intransitively "arise out or up, come forth, come up, come out, rise," from assimilated form of ex "out" (see ex-) + mergere "to dip, sink" (see merge). The notion is of rising from a liquid by virtue of buoyancy. Related: Emerged; emerging.